Wowbagger the I.P.

Hello,

The previous owner wired the fans in parallel (yay) to a toggle switch on the dash (what?) - I'm working to revert the cooling fans to act off of the thermoswitch.

The wires which normally plug into the cooling fan still get power when I jump the GRD and TFA pins in the diagnostics box, so it appears that all I must do is rewire the fans to plug into the normal place.

Is there any particular reason to run it off of a manual switch? Is there anything I should check before rewiring it as described and starting the car again?

I'm guessing I could check the thermoswitch (pot of water) and relay (bypass thermoswitch to ground) in isolation first.

Thanks.

matthewdesigns

iTrader: (8)

I just picked up another Miata project and the fans are wired the same way. The PO said they "just stopped working" and then rewired them. Seems like a massive waste of time to have done this. I suspect the thermoswitch as well.

Wowbagger the I.P.

a) I checked the relay - it clicks when the thermo switch is bypassed

b) I pulled the thermo switch and tried to test it in a pot of boiling water - my mom held it with some tongs while I used a multimeter to test for continuity, and it was dead. It's supposed to close at 207 deg F, but it wasn't doing anything in boiling water.

I can get a new switch for $15 at RockAuto or $50+ from the Mazda dealer. What's the catch? Some say that the auto parts store variety don't close the circuit at a low enough temp, some say they work fine.

sixshooter

iTrader: (12)

I've never had a problem with Rockauto.

hornetball

iTrader: (4)

+1 on Rockauto.

I suspect different dealers mark-up differently. If I need something OEM, I usually go to Rosenthal or Jim Ellis on the interweb. They're pretty reasonable. BTW, virtually EVERY part on your car is still available from Mazda. Another reason to love Miatas.

Wowbagger the I.P.

I ended up paying twice as much ($30) at a local Autozone because I'm impatient and wanted to be able to return it easily in case of a malfunctioning unit. Throw in a lifetime warranty and the fact it's not made in China and I'm pleased.

I wired the fans in parallel to the original cooling fan connector and wrapped up the whole deal in plastic sheathing. Now I have clean, solid, and protected wiring . . . for the fan. There are many more messes to sort out.

Fun fact: The PO ran one wire from the fans to the switch under the dash and another all the way to the battery. The only reason I can see to do that is that he didn't want to replace (or didn't know to replace) the thermo switch.